OP, if you want to do serious pvp, take competetive ship like fdl, fas, vulture, alliance ch..., even krait or python (or fgs, fds, clip)
that is nr1 step you need to do, step up and forget about cobra, viper... yes they are ok but not as primary pvp ship (same with big ships)
I cant believe after few answers nobody adviced just that major thing.... to get medium ship.
With small ship it takes too long to kill other pvper in medium ship.
as for weapons, use anything
Ship have to be build for PvP only, so forgot about versatility like f.e. fuel scoop, srv hangar, cargo rack (!), so equip it just for PvP. Lot of shield, and lot of armor. Then come to CG, with your new maxed pvp ship and confidence how long it will hold in a fight, then realise you can be killed faster as you was thinking, then you will improve.... and that is most enjoyable IMO